Surgical instruments are used in various open, endoscopic, and laparoscopic surgeries to perform a variety of tasks. Certain surgical instruments utilize an end effector to manipulate tissue. For example, instruments can include an end effector that can grasp tissue and, in some cases, seal and transect tissue volumes and blood vessels. Some such instruments or devices can generally include opposed jaws for grasping tissue and can also include a cutting mechanism that can be advanced through grasped tissue to transect it. In some instances, the devices can also be configured to apply electrical or other energy to the grasped tissue to seal it before tissue transection is completed. For example, various mono-polar and bi-polar radio frequency (RF) surgical instruments and associated techniques have been developed for sealing tissue volumes and blood vessels. Such devices often utilize electrodes disposed on a face of one or both of the jaws to deliver electrical or other energy to the grasped tissue.
Certain devices can also include the ability to articulate a distal end of the device, such as the jaws or other end effector components. An articulating distal end can allow the jaws or other end effector to be manipulated off a central longitudinal axis of the device to access, or more easily access, areas of a surgical site that would otherwise be difficult or impossible to reach if the end effector were in fixed alignment with a shaft of the device. Further, some such devices can additionally include the ability to rotate the end effector of the device around a central longitudinal axis thereof to reorient the end effector. In some cases, it can be desirable to maintain an ability to rotate the end effector even after it has been articulated into a position offset from a longitudinal axis of the device.
Implementing the ability to rotate an end effector about a central axis thereof, even after articulating the end effector relative to a surgical instrument, can introduce challenges. For example, after the end effector has been articulated and/or rotated, actuating cables extending to the end effector can fail due to kinking, twisting, or other deformation. As a result, additional mechanisms can be required to prevent such failure, but these mechanisms can themselves introduce complexity and potential failure points.
By way of further example, in prior devices slip rings have been utilized to transfer electrical energy to an end effector in a manner that is not susceptible to twisting due to rotation. These components, however, can be more complex, more prone to failure, and less efficient than, e.g., a continuous wire conductor. In another example, rigid shafts utilized to effect rotation of an end effector cannot be employed with an end effector that both rotates and articulates, as the shaft cannot bend through the articulation joint. In still another example, prior devices have included articulation mechanisms that utilize a plurality of control bands to effect articulation, such as oppositely-disposed bands configured to operate in a “push/pull” manner to cause articulation in one direction or another. Some prior articulation mechanisms have further utilized a structure of segmented beads that function similarly to a series of ball-and-socket joints to allow articulation of an end effector. These devices can be complex, expensive, and prone to buckling in certain maneuvers, such as distal advancement and other maneuvers in which the instrument experiences axial compression forces. They also can result in larger devices (e.g., due to the numerous components, such as multiple articulation control bands, components to allow for rotation of the end effector without kinking or twisting, etc.) that are less desirable for certain minimally invasive procedures in which the instrument is introduced through an incision or access port of limited size.
Accordingly, there is a need for improved surgical instruments having articulating and rotating end effectors that have reduced size, complexity, susceptibility to failure, and increased strength, e.g., in axial compressive loading.